Magnetoelectronics devices, spin electronics devices and spintronics devices are synonymous terms for devices that use the effects predominantly caused by electron spin. Magnetoelectronics effects are used in numerous information devices, and provide non-volatile, reliable, radiation resistant, and high-density data storage and retrieval. The numerous magnetoelectronics information devices include, but are not limited to, magnetic random access memory (MRAM), magnetic sensors and read/write heads for disk drives.
Generally, a magnetoelectronics information device is constructed with an array of magnetoelectronics elements (e.g., giant magnetoresistance (GMR) elements or magnetic tunnel junction (MTJ) elements) formed in a substrate that may also include a variety of semiconductor devices, such as, for example, MOSFETs. The magnetoelectronics elements are programmed by the magnetic field created from a current-carrying conductor. Typically, two current-carrying conductors, one formed underneath the magnetoelectronics element (the digit line) and one formed overlying the magnetoelectronics element (the bit line), are arranged in cross point matrix to provide magnetic fields for programming of the magnetoelectronics element.
Advanced semiconductor processes often use metal interconnects for the current-carrying conductors. One method of forming the bit line metal interconnect is by a damascene or inlaid process during which a trench is patterned and etched in a dielectric layer, followed by the deposition of a metal layer within the trench. Flux concentrating systems often are formed proximate to the metal interconnect. Flux concentrating systems typically utilize top cladding layers formed overlying the metal interconnect to concentrate the magnetic flux of the interconnect toward the magnetoelectronics element. Such systems also typically utilize cladding layers formed on the sides of the metal interconnect to focus the magnetic flux to the underlying magnetoelectronics element. Without cladding layers, high currents are required to achieve the desired magnetic field strength. These high currents may adversely affect nearby magnetoelectronics elements not being programmed.
However, prior art methods to provide top cladding layers overlying bit lines have proved unsatisfactory. Such methods often result in roughness of the metal layer of the bit line, which may adversely affect the coercivity of the top cladding layer. Other methods may result in a “magnetic gap” between the cladding layer and the metal layer of the bit line, that is, the distance between the cladding layer and the metal layer of the bit line is sufficiently large that performance of the cladding layer is compromised. Still other methods may result in non-planar top cladding layers that exhibit detrimental magnetic interaction with pre-existing side cladding layers.
Accordingly, it is desirable to provide an improved method for fabricating a flux concentrating system for use in a magnetoelectronics device. Other desirable features and characteristics of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings.